1. Field of the Invention
This invention relates to an image forming apparatus such as a copier or a printer using the electrophotographic process, and particularly to an image forming unit detachably attachable to the image forming apparatus.
2. Description of the Related Art
In an electrophotographic image forming apparatus, a toner image formed on a photosensitive drum, which is an image bearing member, is transferred to a transferring material to thereby form an image, and as a color image forming apparatus, use has been made of one having a construction in which respective color toner images successively formed on a photosensitive drum are superimposed and transferred to an intermediate transferring body, and the color images are collectively transferred to a transferring material. In this case, in order to facilitate the handling of the deterioration of the photosensitive drum, etc. and consumptive members, a unit into which these are made and which is made detachably attachable to the main body of the apparatus has come to be widely used.
In a color image forming apparatus thus using an intermediate transferring body, as shown in Japanese Patent Application Laid-Open No. 8-137181, Japanese Patent Application Laid-Open No. 10-301464 and Japanese Patent Application Laid-Open No. 11-295998, a photosensitive body unit and an intermediate transferring body unit are of independent-unit construction, and are designed to be dismountable when the units have reached the end of their lives or during the treatment of a jam.
The apparatus of Japanese Patent Application Laid-Open No. 8-137181 is of a construction in which a movable side frame on the front of the apparatus is pivotally moved downwardly of the front of the apparatus and opened, whereby the photosensitive body unit and the intermediate transferring body unit are detachably attached from above. Also, in Japanese Patent Application Laid-Open No. 10-301464, the design of the device is such that the photosensitive body unit and the intermediate transferring body unit are detachably attached to movable members that can be horizontally drawn out to the front of the main body of the apparatus independently of each other. These two embodiments carry out the attachment and detachment of the units in a direction parallel to the conveying direction of the transferring material (these will hereinafter be referred to as xe2x80x9cConventional Example 1xe2x80x9d). 
On the other hand, in Japanese Patent Application Laid-Open No. 11-295998, the design of the device is such that the units are slid in a direction perpendicular to the conveying direction of the transferring material and are thereby attached or detached (this will hereinafter be referred to as xe2x80x9cConventional Example 2xe2x80x9d).
The high voltage contact construction of an image forming apparatus like Conventional Example 1 is such that for example, a high voltage contact for receiving the supply of a bias voltage to primary transferring means provided in the intermediate transferring body unit and cleaning means, and the ground contact of a secondary transferring opposed roller are provided on the side of the intermediate transferring body unit, and are connected to contact means constituted by a contact pin and a compression spring provided on the side of a movable body, and are further connected to the main body of the image forming apparatus by the movable body being pushed into the main body of the apparatus.
Also, a high voltage contact for receiving the supply of a bias voltage to charging means provided in the photosensitive body unit is provided on the side or the upper surface of the photosensitive body unit, and is designed to be inserted into the main body of the image forming apparatus and thereby connected thereto, and a high voltage contact portion is provided at a separate position in each unit.
As the construction of the contact portion, besides the aforedescribed construction by the contact pin and the compression spring, one using a leaf spring is popular.
In the image forming apparatus of the construction as shown in Conventional Example 2 wherein each unit is attached or detached by being slid in a direction perpendicular to the conveying direction of the transferring material, it is usual to adopt a construction in which floating connectors provided on the inner side of the sliding direction of each unit and the side of the frame of the main body of the apparatus are connected together by the unit being inserted.
However, the above-described embodiments of the conventional art have suffered from the following problems.
In the image forming apparatus of the construction as shown in Conventional Example 1, a high voltage contact corresponding to each unit is provided on the side of the frame of the main body of the apparatus and therefore, high voltage wiring must be done from a high voltage substrate to respective separate positions, thus leaving problems in terms of the assembling property and cost.
Also, in the image forming apparatus of the construction as shown in Conventional Example 2, an opening portion for attaching and detaching each unit becomes necessary in the frame of the main body of the apparatus, and this adversely affects the rigidity of the frame of the entire apparatus. Further, as in Conventional Example 1, a high voltage contact corresponding to each unit is provided on the side of the frame of the main body of the apparatus and therefore, high voltage wiring must be done from a high voltage substrate to respective separate positions, thus leaving problems in terms of the assembling property and cost.
It is an object of the present invention to provide an image forming unit and an image forming apparatus in which wiring is simplified and the assembling property of the unit is improved.
It is another object of the present invention to provide an image forming unit and an image forming apparatus in which the number of the constituent parts of the unit is decreased to thereby achieve the downsizing and reduced cost of the whole of the main body of the apparatus.
It is another object of the present invention to provide an image forming unit and an image forming apparatus comprising an image bearing body, charging means for charging the image bearing body, a first unit having the image bearing body and the charging means, an intermediate transferring body, transferring means for transferring a toner image on the image bearing body to the intermediate transferring body, and a second unit having the intermediate transferring body and the transferring means, one of the first unit and the second unit being supplied with electric power through the other unit.
It is another object of the present invention to provide an image forming unit and an image forming apparatus comprising an image bearing body, an intermediate transferring belt to which a toner image on the image bearing body is transferred, and a rotary member over which the intermediate transferring belt is passed, the rotary member being an opposed electrode common to a plurality of members supplied with electric power.
Further, objects of the present invention will become apparent from the following description.